caa a22 4500 397494246 CHVBK 20180308164517.0 cr unu---uuuuu 161202e199507 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a124885 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a124885 Lymphocyte Isoforms of Mouse p50 LSP1, Which Are Phosphorylated in Mitogen-Activated T Cells, Are Formed through Alternative Splicing and Phosphorylation [Elektronische Daten] [Naoki Matsumoto, Kiyoshi kita, Somei Kojima, Kazuo Yamamoto, Tatsuro Irimura, Masaru Miyagi, Susumu Tsunasawa, Satoshi Toyoshima] p50 is phosphorylated in mitogen-stimulated T cells, and translocated from the membrane to the cytosol after activation of protein kinase C. Sequence analysis of p50 revealed that it is identical with LSP1, a putative calcium-binding and actin-binding protein. The lymphocyte form of p50 exhibits heterogeneity in the apparent molecular mass on SDS-PAGE, 50 and 52 kDa (pp50 and pp52), and each isoform exhibits hetrogeneity in the isoelectric point, when examined by two-dimensional PAGE. When the two molecular mass variants of p50 were dephosphorylated with alkaline phosphatase, both isoforms showed the same apparent molecular mass of 50 kDa on SDS-PAGE, but could be distinguished by their distinct isoelectric points. Dephosphorylated pp50 (p50a) has an acidic pI compared with dephosphorylated pp52 (p50b). Comparison of the peptide maps of purified p50a and p50b on HPLC revealed that the difference was limited to one peptide peak. NH2-terminal sequence and mass spectrometric analyses of these peptides showed that the peptides derived from p50a and p50b had the same NH2-terminal amino acid sequence up to eight residues, but had distinct molecular masses, 5, 533.4 and 6, 318.6Da, respectively. These data suggested that pp52 (p50b) is the product of the previously cloned cDNA and the reduction in the molecular mass of the p50a-derived peptide could be explained by deletion of six amino acid residues, EHLIRH or HLJRHQ. To verify this prediction, we examined the mRNA encoding p50 by means of the reverse transcriptase-polymerase chain reaction and found the presence of an mRNA that had a deletion of 18 bp, that results in a deletion of six amino acid residues, HLERHQ (158-163), after translation. These data, and the results of transfection and expression of the two types of p50 cDNA in BALB/3T3 fibroblasts indicate that alternative splicing and phosphorylation generate the multiple isoforms of p50 in lymphocytes. © by the Journal of Biochemistry Regular Papers nationallicence Key words nationallicence alternative splicing nationallicence isoform nationallicence LSP1 nationallicence p50 nationallicence phosphorylation nationallicence Matsumoto Naoki Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut kita Kiyoshi Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut Kojima Somei Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut Yamamoto Kazuo Department of Cancer Biology and Molecular Immunology, Faculty of Pharmaceutical Sciences, The University of Tokyo Bunkyo-ku, Tokyo 113 aut Irimura Tatsuro Department of Cancer Biology and Molecular Immunology, Faculty of Pharmaceutical Sciences, The University of Tokyo Bunkyo-ku, Tokyo 113 aut Miyagi Masaru Biomedical Group, Takara Shuzo Co., Ltd. Otsu, Shiga 520-21 aut Tsunasawa Susumu Biomedical Group, Takara Shuzo Co., Ltd. Otsu, Shiga 520-21 aut Toyoshima Satoshi Department of Biochemistry, Hoshi University Shinagawa-ku, Tokyo 142 aut The Journal of Biochemistry Oxford University Press 118/1(1995-07), 237-243 0021-924X 118:1<237 1995 118 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a124885 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a124885 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Matsumoto Naoki Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut NATIONALLICENCE 700 1- kita Kiyoshi Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut NATIONALLICENCE 700 1- Kojima Somei Department of Parasitology, Institute of Medical Science, The University of Tokyo Minato-kuTokyo 108 aut NATIONALLICENCE 700 1- Yamamoto Kazuo Department of Cancer Biology and Molecular Immunology, Faculty of Pharmaceutical Sciences, The University of Tokyo Bunkyo-ku, Tokyo 113 aut NATIONALLICENCE 700 1- Irimura Tatsuro Department of Cancer Biology and Molecular Immunology, Faculty of Pharmaceutical Sciences, The University of Tokyo Bunkyo-ku, Tokyo 113 aut NATIONALLICENCE 700 1- Miyagi Masaru Biomedical Group, Takara Shuzo Co., Ltd. Otsu, Shiga 520-21 aut NATIONALLICENCE 700 1- Tsunasawa Susumu Biomedical Group, Takara Shuzo Co., Ltd. Otsu, Shiga 520-21 aut NATIONALLICENCE 700 1- Toyoshima Satoshi Department of Biochemistry, Hoshi University Shinagawa-ku, Tokyo 142 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 118/1(1995-07), 237-243 0021-924X 118:1<237 1995 118 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford